1. Field of the Invention
Aspects of embodiments relate to a flexible jelly-roll type secondary battery.
2. Description of the Related Art
Unlike non-rechargeable primary batteries, secondary batteries are chargeable and dischargeable batteries. The range of use thereof is very wide, from small sized portable electronic devices to large scale electrical and electronic apparatuses such as hybrid vehicles or the like.
Secondary batteries are configured by allowing electrode assemblies, having separation films as insulators provided therein and interposed between anodes and cathodes, to be embedded in cases, and installing cap assemblies having external terminals provided therewith in the cases. The anodes and the cathodes are formed of coated portions formed by coating current collectors with an active material and uncoated portions. The uncoated portions of the anodes and the cathodes include electrode taps collecting a current generated in the anodes and the cathodes, respectively, and the electrode taps are attached to electrode assemblies through welding or the like to induce the current generated in the anodes and the cathodes to anode terminals and cathode terminals.
In recent years, as device design has become a significant factor in consumers' choice of products, various types of batteries have been required to accommodate various designs aiming for ergonomic design. In particular, requirements for batteries having a curved shape, able to be stably mounted in devices having a design in which outer surfaces thereof are curved to reduce unnecessary space consumption, have increased.
However, when portions coated with an active material are curved, problems in which the portions are irreversibly transformed and short circuits in electrodes occur due to the separation of an electrode active material from current collector surfaces may occur such that stability of batteries may be deteriorated.